1. Field of the Invention
The present invention relates to a sheet folding apparatus, and more particularly to control of a sheet positioning guide provided in a sheet folding section thereof
2. Description of the Related Art
A conventional sheet folding apparatus is provided with a sheet folding section which first folds a sheet in a direction perpendicular to a conveying direction, and next folds the sheet in a direction along the conveying direction. FIG. 3 shows a schematic structure of one example of the sheet folding apparatus.
Referring to FIG. 3, the letter A denotes a sheet feeding section, the letter B denotes a sheet conveying section, the letter C denotes a first sheet folding section, the letter D denotes a second sheet folding section, and the letter E denotes a third sheet folding section.
The sheet feeding section A has a sheet supply table 1 arranged for up-and-down movement and supporting a sheet bundle thereon, and a roller 2 feeding the uppermost sheet P of the sheet bundle on the sheet supply table 1 to the sheet conveying section B one by one. The sheet conveying section B has a conveyer belt 3 conveying the sheet P supplied from the sheet feeding section A to the sheet folding section C, and a positioning ruler 4 arranged parallel with the conveying direction for positioning the sheet P. The conveyer belt 3 is arranged at an angle to the positioning ruler 4, so that the sheet P is conveyed by the conveyer belt 3 while one side of the sheet P being aligned along the positioning ruler 4. The positioning ruler 4 is engaged with a feeding screw 6 driven by a motor 5 for movement in a direction perpendicular to the conveying direction.
The first sheet folding section C folds the sheet P in the direction perpendicular to the conveying direction. The first sheet folding section C has a folding buckle (not shown), and a group of folding rollers 7 extending in the direction perpendicular to the conveying direction. A portion from a leading edge to a fold position of the sheet P is inserted to the folding buckle, and a trailing portion of the sheet P is inserted downward between a pair of folding rollers 7, and the sheet P is folded in the direction perpendicular to the conveying direction. Thereafter, the sheet P is fed to the second sheet folding section D through a gear 8 for applying a perforated line (or a bent line).
The second sheet folding section D folds the sheet P in the direction along the conveying direction. The second sheet folding section D has a folding knife 9 arranged at a position aligning with the gear 8 for up-and-down movement and extending along the conveying direction, a pair of folding rollers 10 arranged beneath the folding knife 9 and extending along the folding knife 9, and a stopper 12 extending in the direction perpendicular to the conveying direction for receiving the leading end of the sheet P delivered from the first sheet folding section C. A position of the stopper 12 is adjustable in the direction along the conveying direction by a belt driving mechanism. The belt driving mechanism has a pair of rollers 30a and 30b extending perpendicularly to the conveying direction and arranged parallel with each other at a spacing therebetween for rotation around the axes thereof. One roller 30a is driven by a motor 13 and endless belts 14 are extended between the opposed end portions of the pair of rollers 30a and 30b through pulleys. Both end portions of the stopper 12 are attached to the endless belt 14, and the position of the stopper 12 can be adjusted in the direction along the conveying direction by the drive of the motor 13. A first guide 11a and a second guide 11b are arranged on either side of the folding knife 9 at a spacing therebetween and parallel with the folding knife 9. The first guide 11a functions as a reference guide for positioning the sheet P in the direction perpendicular to the conveying direction, and the second guide 11b is resiliently biased a spring (not shown) in such a manner that the sheet P pressed by the second guide 11b at its one side and abutted on the first guide 11a at its other side. The first guide 11a and the second guide 11b are detachably mounted to the stopper 12. The sheet P delivered from the first sheet folding section C is stopped by the stopper 12, and is thereafter positioned by the first and second guides 11a and 11b such that the perforated line of the sheet P is aligned with the folding knife 9. Thereafter, the folding knife 9 is moved down, and the sheet P is nipped between the pair of folding rollers 10, folded in the direction along the conveying direction, and fed to the third sheet folding section E.
The third sheet folding section E is arranged adjacent the second sheet folding section D in the direction perpendicular to the conveying direction for folding the sheet P delivered from the second sheet folding section D in the direction along the second conveying direction (the direction perpendicular to the conveying direction from the sheet feeding section A to the second sheet folding section D). The third sheet folding section E has a folding knife 15 arranged for up-and-down movement and extending along the second conveying direction, a pair of folding rollers 16 arranged beneath the folding knife 15 and extending along the folding knife 15, and a stopper 18 extending perpendicularly to the second conveying direction for receiving the leading end of the sheet P delivered from the second sheet folding section D. A position of the stopper 18 is adjustable in the direction along the second conveying direction by a belt driving mechanism. The belt driving mechanism has a pair of rollers 31a and 31b extending perpendicularly to the second conveying direction and arranged parallel with each other at a spacing therebetween for rotation around the axes thereof One roller 31a is driven by a motor 19 and endless belts 20 are extended between the opposed ends of the pair of rollers 31a and 31b through pulleys. Both end portions of the stopper 1 are attached to the endless belts 20, and the position of the stopper 18 can be adjusted in the direction along the conveying direction by the drive of the motor 19. A first guide 17a and a second guide 17b are arranged on either side of the folding knife 15 at a spacing therebetween and parallel with the folding knife 15. The first guide 17a functions as a reference guide for positioning the sheet P in the direction perpendicular to the second conveying direction, and the second guide 17b is resiliently biased by a spring (not shown) in such a manner that the sheet P is pressed by the second guide 17b at its one side and abutted on the first guide 17a at its other side. The first and second guides 17a and 17b are detachably mounted to the stopper 18. The sheet P delivered from the second sheet folding section D is stopped by the stopper 18, and is thereafter positioned by the first and second guides 17a and 17b. Thereafter, the folding knife 15 is moved down, and the sheet P is inserted between a pair of folding rollers 16, folded in the direction along the conveying direction, and discharged from the sheet folding apparatus.
Since the position of the gear 8, the positions of the folding knife 9 and the folding rollers 10 of the second sheet folding section D, and the positions of the folding knife 15 and the folding rollers 16 of the third sheet folding section E are previously fixed when the sheet folding apparatus is actuated, the position of the positioning ruler 4 of the sheet conveying section B is set by driving the motor 5 so as to align the fold position of the sheet with the gear 8 and the folding knife 9 in conformity with a dimension in the direction perpendicular to the conveying direction of the sheet. Next, the first guide 11a of the second sheet folding section D is attached to the stopper 12 so as to be aligned with the set position of the positioning ruler 4, and the second guide 11b is next attached to the stopper 12 so as to be spaced from the first guide 11a at the distance corresponding to the dimension of the sheet in the direction perpendicular to the conveying direction.
Next, the first guide 17a of the third sheet folding section E is attached to the stopper 18 so as to align the fold position of the sheet, which is delivered from the second sheet folding section D, with the folding knife IS, and then the second guide 17b is attached to the stopper 18 so as to be spaced from the first guide 17a at the distance corresponding to the dimension of the sheet in the direction perpendicular to the second conveying direction. Furthermore, the position of the stopper 12 is set by driving the motor 13 of the second sheet folding section D so as to be aligned with the guide 17a of the third sheet folding section E.
After the adjustment of the position of each of the constituent elements, the sheet folding apparatus is actuated, and the sheet P supplied from the sheet feeding section A is guided by the positioning ruler 4 and folded into two in the direction perpendicular to the conveying direction in the first sheet folding section C, is thereafter folded into two in the direction along the conveying direction in the second sheet folding section D, is thereafter fed to the third sheet folding section E in the direction perpendicular to the previous conveying direction, is folded into two in the direction along the conveying direction, and is discharged. In this case, a eight-folded quire is formed in accordance with a series of sheet folding operations.
There is a case that the fold positions of the sheet are out of alignment in the second sheet folding section D and the third sheet folding section E during the sheet folding operation. In this case, it is necessary to adjust the position of the positioning ruler 4 of the sheet conveying section B, the positions of the first and second guides 11a and 11b of the second sheet folding section D, the positions of the first and second guides 17a and 17b of the third sheet folding section E, and the position of the stopper 12 of the second sheet folding section D. However, since there is a risk that a lot of wasted sheets are generated if the adjustment is executed during the operation, in most cases, such adjustment work is executed after temporarily stopping the sheet folding apparatus. Furthermore, there are problems that a lot of labor hour is required for the adjustment work, and an operation efficiency is lowered due to the stop of the sheet folding apparatus.